i2c: add register access API
Add API for reading, writing and updating internal registers of I2C
devices. This API is meant to be used as a simpler way of communicating
with I2C devices that have 8-bit internal registers.
Change-Id: I7280eb530039aa10ad9cc19c1c309c7a2f473eb4
Signed-off-by: Bogdan Davidoaia <bogdan.m.davidoaia@intel.com>
diff --git a/include/i2c.h b/include/i2c.h
index d1c699c..05c114a 100644
--- a/include/i2c.h
+++ b/include/i2c.h
@@ -239,6 +239,151 @@
}
/**
+ * @brief Read multiple bytes from an internal address of an I2C device.
+ *
+ * This routine reads multiple bytes from an internal address of an
+ * I2C device synchronously.
+ *
+ * @param dev Pointer to the device structure for the driver instance.
+ * @param dev_addr Address of the I2C device for reading.
+ * @param start_addr Internal address from which the data is being read.
+ * @param buf Memory pool that stores the retrieved data.
+ * @param num_bytes Number of bytes being read.
+ *
+ * @retval 0 If successful.
+ * @retval Negative errno code if failure.
+ */
+static inline int i2c_burst_read(struct device *dev, uint16_t dev_addr,
+ uint8_t start_addr, uint8_t *buf,
+ uint8_t num_bytes)
+{
+ struct i2c_driver_api *api;
+ struct i2c_msg msg[2];
+
+ msg[0].buf = &start_addr;
+ msg[0].len = 1;
+ msg[0].flags = I2C_MSG_WRITE | I2C_MSG_RESTART;
+
+ msg[1].buf = buf;
+ msg[1].len = num_bytes;
+ msg[1].flags = I2C_MSG_READ | I2C_MSG_STOP;
+
+ api = (struct i2c_driver_api *)dev->driver_api;
+ return api->transfer(dev, msg, 2, dev_addr);
+}
+
+/**
+ * @brief Write multiple bytes to an internal address of an I2C device.
+ *
+ * This routine writes multiple bytes to an internal address of an
+ * I2C device synchronously.
+ *
+ * @param dev Pointer to the device structure for the driver instance.
+ * @param dev_addr Address of the I2C device for writing.
+ * @param start_addr Internal address to which the data is being written.
+ * @param buf Memory pool from which the data is transferred.
+ * @param num_bytes Number of bytes being written.
+ *
+ * @retval 0 If successful.
+ * @retval Negative errno code if failure.
+ */
+static inline int i2c_burst_write(struct device *dev, uint16_t dev_addr,
+ uint8_t start_addr, uint8_t *buf,
+ uint8_t num_bytes)
+{
+ struct i2c_driver_api *api;
+ struct i2c_msg msg[2];
+
+ msg[0].buf = &start_addr;
+ msg[0].len = 1;
+ msg[0].flags = I2C_MSG_WRITE;
+
+ msg[1].buf = buf;
+ msg[1].len = num_bytes;
+ msg[1].flags = I2C_MSG_WRITE | I2C_MSG_STOP;
+
+ api = (struct i2c_driver_api *)dev->driver_api;
+ return api->transfer(dev, msg, 2, dev_addr);
+}
+
+/**
+ * @brief Read internal register of an I2C device.
+ *
+ * This routine reads the value of an 8-bit internal register of an I2C
+ * device synchronously.
+ *
+ * @param dev Pointer to the device structure for the driver instance.
+ * @param dev_addr Address of the I2C device for reading.
+ * @param reg_addr Address of the internal register being read.
+ * @param value Memory pool that stores the retrieved register value.
+ *
+ * @retval 0 If successful.
+ * @retval Negative errno code if failure.
+ */
+static inline int i2c_reg_read_byte(struct device *dev, uint16_t dev_addr,
+ uint8_t reg_addr, uint8_t *value)
+{
+ return i2c_burst_read(dev, dev_addr, reg_addr, value, 1);
+}
+
+/**
+ * @brief Write internal register of an I2C device.
+ *
+ * This routine writes a value to an 8-bit internal register of an I2C
+ * device synchronously.
+ *
+ * @param dev Pointer to the device structure for the driver instance.
+ * @param dev_addr Address of the I2C device for writing.
+ * @param reg_addr Address of the internal register being written.
+ * @param value Value to be written to internal register.
+ *
+ * @retval 0 If successful.
+ * @retval Negative errno code if failure.
+ */
+static inline int i2c_reg_write_byte(struct device *dev, uint16_t dev_addr,
+ uint8_t reg_addr, uint8_t value)
+{
+ uint8_t tx_buf[2] = {reg_addr, value};
+
+ return i2c_write(dev, tx_buf, 2, dev_addr);
+}
+
+/**
+ * @brief Update internal register of an I2C device.
+ *
+ * This routine updates the value of a set of bits from an 8-bit internal
+ * register of an I2C device synchronously.
+ *
+ * @param dev Pointer to the device structure for the driver instance.
+ * @param dev_addr Address of the I2C device for updating.
+ * @param reg_addr Address of the internal register being updated.
+ * @param value Value for updating internal register.
+ * @param mask Bitmask for updating internal register.
+ *
+ * @retval 0 If successful.
+ * @retval Negative errno code if failure.
+ */
+static inline int i2c_reg_update_byte(struct device *dev, uint8_t dev_addr,
+ uint8_t reg_addr, uint8_t value,
+ uint8_t mask)
+{
+ uint8_t old_value, new_value;
+ int rc;
+
+ rc = i2c_reg_read_byte(dev, reg_addr, dev_addr, &old_value);
+ if (rc != 0) {
+ return rc;
+ }
+
+ new_value = (old_value & ~mask) | (value & mask);
+ if (new_value == old_value) {
+ return 0;
+ }
+
+ return i2c_reg_write_byte(dev, dev_addr, reg_addr, new_value);
+}
+
+/**
* @brief Suspend an I2C driver.
* @param dev Pointer to the device structure for the driver instance.
*
